Method of preparing drawing data for charged beam exposure system

Abstract

A method of preparing drawing data for a charged beam exposure system includes: constructing, from pattern data having a multiple hierarchical structure, reiterative units disposed in an array without any gap formed therebetween; converting the pattern data into first figure processing data including a total figure and reiterative units within the total area; dividing the total area of the first figure into equal area processing data fields for a charged beam exposure system, each field including a whole number of reiterative units, if any, thereby producing second figure processing data; performing figure modification processing with respect to features in a field outside reiterative units in the field and separately with respect to the reiterative units within the field, thereby producing third figure processing data; and converting the third figure processing data into suitable drawing data for the charged beam exposure system.

What is claimed is: 
     
       1. A method of preparing drawing data for a charged beam exposure system comprising: constructing from pattern data describing features representing elements in a semiconductor integrated circuit, a pattern having a total area, at least one reiterative unit, each reiterative unit representing a repeating sub-pattern of features, a plurality of identical reiterative units being disposed in a respective array, the respective reiterative units being contiguously disposed without any gaps therebetween in the respective arrays, each array representing a subarea within the total area;   converting the pattern data into first figure processing data including pattern data for the total area and for each of the sub-areas and corresponding reiterative units;   dividing the first figure processing data into a plurality of fields, each field chosen to accommodate characteristics of a charged beam exposure system and representing a portion of the total area, some of the fields representing areas including part or all of an array, each field including any part of an array including only a whole number of reiterative units of the respective array, to form second figure processing data;   performing figure modification processing of the second figure processing data for each field, separately processing second figure processing data representing areas in each field, if any, not including any reiterative units and representing areas in each field, if any, including reiterative units to form third figure processing data; and   converting the third figure processing data into drawing data for the charged beam exposure system.   
     
     
       2. A method according to claim 1 wherein figure modification processing includes removing data representing areas in each field not within a reiterative unit. 
     
     
       3. A method according to claim 1 wherein figure modification processing includes tone reversal processing. 
     
     
       4. A method according to claim 1 wherein figure modification processing includes modification of second figure processing data by magnifying and reducing areas represented by the second figure processing data. 
     
     
       5. A method according to claim 4 including, when the magnifying and reducing processing is performed, removing a peripheral portion of an array of the reiterative units. 
     
     
       6. A method according to claim 4 including, if at least one reiterative unit intrudes into one of the fields, said magnifying and reducing processing for the field excluding the at least one reiterative unit includes the data for the reiterative units disposed adjacent the area and within the field excluding the at least one reiterative unit. 
     
     
       7. A method according to claim 4 including performing said magnifying and reducing processing for a field with the reiterative units that are arrayed around a selected reiterative unit in the field. 
     
     
       8. A method according to claim 1 including, if each of the reiterative units is larger than a pitch of an array because the reiterative units overlap each other, defining each reiterative unit as a region defined by the pitch of the array and determining the array area by removing a peripheral portion of a region corresponding to the center of the array and the reiterative units adjacent the center.